Cavity-resonator magnetron



June 5, 1956 J. VERWEEL 2,749,477

CAVITY-RESONATOR MAGNETRON Filed March 18, 1952 CAVITY-RESONATOR MAGNETRON Jan Verweel, Eindhoven, Netherlands, assignor to Haltford National Bank and Trust Company, Hartford, Conn., as trustee This invention relates to a magnetron of the resonant cavity type.

It is an object of the invention to provide a novel construction for a magnetron of the resonant cavity type which greatly simplifies the assembling of such a magnetron.

This and other objects of the invention will be best understood from the following description.

According to the invention, a magnetron of the resonant cavity type comprises a pair of terminal plates each having a first cylindrical recess of given diameter concentric with a second cylindrical recess having alarger diameter than the given diameter and a pair of coaxial grooves opening into the cylindrical recesses. An anode block having a plurality of resonant cavities fits within the larger cylindrical recesses of the terminal plates so that the opposing surfaces of the plates are in engagement with one another. The anode block is also provided with a projecting portion which fits within the coaxial grooves and which contains a groove which connects with one of the cavities. The groove of the projecting portion of the anode block and the coaxial grooves cooperate to form an H-shaped channel which is utilized to transfer the energy generated within the resonant cavities to a wave-guide which, in turn, transmits the energy to an external circuit. With such an arrangement, soldering of the terminal plates along their engaged surfaces will provide a vacuum-tight enclosure for the magnetron. Moreover, the solder is prevented from flowing into the cylindrical recesses or the H-shaped channel and impairing the electrical characteristics' of the magnetron.

In a preferred embodiment, the terminal plates are provided with a recess shaped to form a wave-guide adjoining the H-shaped channel and having a length of about half the length of a wave-guide for the magnetron. This arrangement avoids the separate operation of soldering of the wave-guide to the magnetron.

The invention will now be described with reference to the accompanying drawing wherein:

Fig. 1 is a perspective view of one form of terminal plate for a magnetron in accordance with the invention;

Fig. 2 is a plan view of an anode block in accordance with the invention;

Fig. 3 is an end view of an assembled magnetron comprising the terminal plate shown in Fig. 1 and the anode block shown in Fig. 2;

Fig. 4 is a partial cross-sectional view of the assembled magnetron showing the cathode mounted in position.

Referring to Figs. 1, 2 and 3, a magnetron comprises a pair of terminal plates 1, 2 and an anode block 6. The terminal plate 1 has a cylindrical recess 3 merging into a narrower cylindrical recess 7 to form an edge 4 located at a distance from an upper surface 5 of the plate 1 equal to about half the thickness of the anode block 6. The narrowed portion 7 of the cylindrical cavity is utilized for providing end pieces 20, a cathode 21 and leads 22 (Fig. 4) for the magnetron and also serves as an end space therefor. The cylindrical cavity 3, 7 merges on one side nited States Patent O 2 into a straight groove 8 having plane walls 9, the edge 4 extending on both sides as an edge 10.

The anode block 6 comprises a body portion shaped to fit within the larger cylindrical recess 3 and a projection 11 shaped to fit into the groove 8 which is split by means of a groove 12 extending into one of a plurality of resonant cavities 13 in the anode block 6. When the anode block 6 and the two terminal plates 1, 2 are assembled, the groove 12 of the projection 11, together with the narrow portions 14 of the groove 8, constitute an H-shaped channel (Fig. 3) which merges into a hollow wave-guide of which a portion 15, preferably half, is formed in each of the terminal plates 1, 2 by an extension 17 in such manner that the short side of the portion 15 of the waveguide extends parallel to the limbs of the H-shaped channel. The portion 15 of the hollow wave-guide is adapted to be closed by a glass window, which is not shown for the sake of clarity.

In order to avoid leakage of energy in coupling the portion of the hollow wave-guide 15 with a subsequent waveguide, a circular groove 16 is provided around the area at which the glass window is provided having a depth about equal to a quarter of a wave-length of the electrical oscillation occurring within the magnetron and having its upper edge approximately at a quarter of a wavelength from the hollow wave-guide.

With the foregoing construction, current paths are not interrupted by a welding seam anywhere along the path where the current flows. Furthermore, the above-described construction prevents solder, which serves to cement the closing plates together along their engaged surfaces, from flowing into the end spaces 7, the H- shaped channel or the resonant cavity 13.

While I have thus described my invention with specific examples and embodiments thereof, other modifications will be readily apparent to those skilled in the art without departing from the spirit and the scope of the invention as defined in the appended claims.

What I claim is:

1. A magnetron of the resonant cavity type comprising a pair of terminal plates each having a first cylindrical recess of given diameter and a second cylindrical recess having a larger diameter than said given diameter and concentric with the first cylindrical recess and two aligned communicating grooves opening into said cylindrical recesses, an anode block enclosed completely between said terminal plates comprising a main body portion having a shape which fits within said second cylindrical recesses of the terminal plates so that the opposing surfaces of the plates are in engagement with one another and a central bore extending through said body portion, a cathode member disposed within said bore, said anode block also defining a plurality of resonant cavities and having a projecting portion fitting within a portion of said aligned grooves and defining a groove extending therethrough which connects with one of said cavities, the groove in said projecting portion and the unoccupied portion of the aligned grooves in said terminal plates cooperating to form an H-shaped channel for transferring the energy generated within the resonant cavities.

2. A magnetron of the resonant cavity type comprising a pair of terminal plates each having a first cylindrical recess of given diameter and a second cylindrical recess having a larger diameter than said given diameter and concentric with the first cylindrical recess and two aligned communicating grooves opening into said cylindrical recesses, an anode block enclosed completely between said terminal plates comprising a main body portion having a shape which fits within said second cylindrical recesses of the terminal plates so that the opposing surfaces of the plates are in engagement with one another and a central bore extending through said body portion, a cathode ther having a recess of rectangular shape adjoining the 10 H-shaped channel, and solder means securing together the terminal plates along their engaged surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 2,466,922 Wax Apr. 12, 1949 2,523,841 Nordsieck Sept. 26, 1950 2,564,716 Okress Aug. 21, 1951 2,579,654 Derby Dec. 25, 1951 

